Answer:
0.0468 g.
Explanation:
- The decay of radioactive elements obeys first-order kinetics.
- For a first-order reaction: k = ln2/(t1/2) = 0.693/(t1/2).
Where, k is the rate constant of the reaction.
t1/2 is the half-life time of the reaction (t1/2 = 1620 years).
∴ k = ln2/(t1/2) = 0.693/(1620 years) = 4.28 x 10⁻⁴ year⁻¹.
- For first-order reaction: <em>kt = lna/(a-x).</em>
where, k is the rate constant of the reaction (k = 4.28 x 10⁻⁴ year⁻¹).
t is the time of the reaction (t = t1/2 x 8 = 1620 years x 8 = 12960 year).
a is the initial concentration (a = 12.0 g).
(a-x) is the remaining concentration.
∴ kt = lna/(a-x)
(4.28 x 10⁻⁴ year⁻¹)(12960 year) = ln(12)/(a-x).
5.54688 = ln(12)/(a-x).
Taking e for the both sides:
256.34 = (12)/(a-x).
<em>∴ (a-x) = 12/256.34 = 0.0468 g.</em>
Answer:
V₂ = 15.3
Explanation:
Given data:
Initial volume = 12.0 L
Initial temperature = 20°C
Final temperature =100°C
Final volume = ?
Solution:
First of all we will convert the temperature into kelvin.
20°C + 273 = 293 K
100°C + 273 = 373 K
Formula:
V₁/T₁ = V₂/T₂
V₁ = Initial volume
T₁ = Initial temperature
V₂ = Final volume
T₂ = Final temperature
Now we will put the values in formula.
V₁/T₁ = V₂/T₂
V₂ = V₁T₂/T₁
V₂ = 12.0 L × 373 K / 293 k
V₂ = 4476 L.K /293 k
V₂ = 15.3
V₂ = 1566 L.K / 298 K
V₂ = 5.3 L
Answer:
The correct answer is - Frequency is the number of wavelengths, which is measured in hertz.
Explanation:
Frequency is the number of waves that go through a fixed point at a particular time. Hertz is the SI unit for frequency which means that one hertz is equal to a unit number of waver passes in a unit time to a fixed point.
As the frequency of a wave increases which means the number of waves increases in the unit time, the shorter the wavelength will be.
a higher frequency wave has more energy than a lower frequency wave with the same amplitude.
3rd Answer. Rays reflect in random directions
